pic: Is this corner considered protected?

[joeweber]

There are many different views of this question. I thank all for there response. The one consistent thing that I have found is that even if it is legal to do it still may be turned down by the inspector. GDC will only refer you to the rules.

If we turn the corner/angle into a curve will it no longer becomes a problem.

Per GDC
3: A "C" configuration chassis for the ROBOT would be legal if, and only if, it satisfies all applicable Robot Rules.
4: A specific minimum radius threshold to determine the difference between corners and curves has not been, and will not be, defined. A "corner" will be determined to be a "corner" when upon inspection any reasonably astute observer perceives it to be a "corner" and not a curve.

[dtengineering]

I've been thinking of a better way to phrase this whole bumper rule thing so that it would serve the purpose and intent of the rule, be easy to test, unambiguous and yet simply and clearly stated.

I would suggest that the GDC could simplify this whole bumper thing by stating:

"When a robot, with trailer attached, approaches a wall, the first part of the robot or trailer to contact the wall shall be a bumper. This may be tested by pushing a 2x4 (representing a long wall) edgewise along the ground towards the robot. If the edge of the 2x4 touches any part of the robot, the robot is not protected."

But... there might be weaknesses in that rule that could lead to ambiguity when inspected by 1300+ teams. I don't envy the GDC their job and support/understand/appreciate their rulings 99.9% of the time. The other .1% of the time, I simply accept the ruling. Like I have a choice!

Jason

Jason

[Scott Hill]

Jason,

I really like your simple 2x4 test. It is unambiguous, easy to apply, and virtually the same as the vertical wall sentence from the lead paragraph of <R08>. I share your appreciation for the GDC and their efforts in a difficult task. The thing that makes this so critical is that there may well be many teams that show up at regionals (not to mention half way thru build season) with robots that may not comply with whatever the lead inspectors interpretation is and possibly face an insurmountable task to make their robot compliant.

Scott

[MamaSpoldi]

No one has addressed this part of these bumpers... the mitered corners of the plywood backing. This is not legal per rule <R08>.O (see also figure 8-4):

"The BUMPER backing must not extend beyond the “edge” of the ROBOT. The backing of adjacent BUMPER segments must not attach to each other if the attachment would require that the joint extend into the corner (see Figure 8 – 4)."

The pool noodles can wrap around the corner, but the plywood backing must stop at the edge of the frame. (You can see this is figure 8-2 as well, but you may have to zoom in a little to see it clearly.)

Note that in part N of this rule the statement that: " 'Hard' parts of the BUMPER (i.e. plywood backing, fastening system, and clamping angles) may extend up to a maximum of one inch beyond the BUMPER PERIMETER." is referring to the thickness of the backing (ie. the extension perpendicular to the bumper perimeter) rather than the length of the backing.

[This is also clarified in this Q&A posting: http://forums.usfirst.org/showthread.php?t=11279]

Also, regarding the corner protection, I would recommend also reviewing the answer given in this Q&A: http://forums.usfirst.org/showthread.php?t=11236. Our team had similar concerns about our bumper configuration. I agree that if there are doubts it is a good idea to opt for a less controversial implementation if it does not sacrifice any functionality.... or at a minimum have a retrofit already determined and ready to go to avoid too much pain if you are overruled.

[johnr]

I would vote no on the bumper,but on a different note,wouldn't this extreme angle of trailer to bot allow an apposing bot to lock you up pretty good. I mean picture a bot driving into the lower left side of picture. Looks like it would be pretty hard to get away.

[Scott Hill]

Hi Al,
It's good to hear from you. For the record this isn't Winnovations robot but I think it raises certain points that are important to discuss.

With respect to your point regarding R08 BUMPER to BUMPER contact, the Manual allows up to 1/3 of the BUMPER PERIMETER to be unprotected by BUMPERS. Any ROBOT with a floor accumulator has to take advantage of this allowable 1/3 unprotected offering. Strict compliance with the BUMPER to BUMPER statement you reference would prohibit such accumulators. I don't think prohibition of floor accumulators is the intent of the GDC and I don't see how the portion of this ROBOT which is unprotected by BUMPERS is any more problematic than a floor accumulator opening/unprotected portion of the BUMPER PERIMETER.

Thanks, I look forward to seeing you, your team, and your ROBOT at Midwest

Scott

[Cory]

Originally Posted by Scott Hill

Hi Al,
It's good to hear from you. For the record this isn't Winnovations robot but I think it raises certain points that are important to discuss.

With respect to your point regarding R08 BUMPER to BUMPER contact, the Manual allows up to 1/3 of the BUMPER PERIMETER to be unprotected by BUMPERS. Any ROBOT with a floor accumulator has to take advantage of this allowable 1/3 unprotected offering. Strict compliance with the BUMPER to BUMPER statement you reference would prohibit such accumulators. I don't think prohibition of floor accumulators is the intent of the GDC and I don't see how the portion of this ROBOT which is unprotected by BUMPERS is any more problematic than a floor accumulator opening/unprotected portion of the BUMPER PERIMETER.

Thanks, I look forward to seeing you, your team, and your ROBOT at Midwest

Scott

Scott, I think if you read this Q&A response, it is pretty clear that you need a bumper segment on both sides of a corner, even though one bumper segment may adequately protect both sides of the corner.

[edit] This Q&A is the one I wanted-it makes it abundantly clear that both sides of the corner must have their own bumper segment.

[Paul Copioli]

Scott,

One important thing to consider is that many of us are picking up from the floor and the "6 inch minimum" + "all sides must have a bumper" GDC clarifications have constrained all of us. The ThunderChicken floor pick-up opening is not as large as we wanted specifically because of the bumper rule. Our robot base design was driven by the bumper rule. Our design is not as cool as we wanted it to be because of the bumper rule.

If any team has a design that looks like the picture at one of my competition, thenn I will bring it up to the inspectors because they will have a significant advantage over everyone esle and it is in violation of written clarifications by the GDC.

The huge advantage on the back of your robot is that you can get your trailer off to the side more to help protect it and you can swing around the trailer more to get a better angle at your opponent.

The advantages on the front side are obvious wrt opening size.

Maybe they left a loophole in on purpose, but if they did, then I say they are lawyering the rules and now we will have to do the same.

For the record, I hate bumpers and designing around the bumper rules, to me, is silly.

[Triple B]

Ya, what Paul said
mike d

[EricH]

Well, you got your official answer.

http://forums.usfirst.org/showthread.php?t=11600

[joeweber]

We figured if we turn the andle corner into a curve we could resove the problem but found the next issue.

Questions about the trailer hitch- I assembles a hitch like the one for the competition trailer (which is different than the team built trailer) and found that the small .615 dia. Hitch pin fits into a 1 inch x 1 inch square tube. There is only about 1 3/8 inch from the pin to the edge of the square tube. Will this limit the amount of turn that the trailer can make and if the aluminum hits the trailer hitch assembly (although it barley fits inside maybe if perfectly centered) will this be a violation of <R18> E..

We want to turn as sharp as possible so we can pin wheel around the trailer for defense.

[Scott Hill]

Cory,
The Q&A answer you refer to follows:

Default Re: Bumper Length
1. The statements are not contradictory. The length of a BUMPER is determined by the portion of the assembly the includes all the required elements (pool noodle, fabric covering, clamping angles, and plywood backing) in the cross-section of the assembly. The length of this portion of the BUMPER assembly must be at least six inches. This is consistent with the previous answers and the statements/drawings in Team Update #2.

2. As indicated in Rule <R08-I>, all exterior corners of the BUMPER PERIMETER must be protected by BUMPERS. Both "sides" of the corner must be protected.

3. Rule <R18-E> requires that the ROBOT be designed such that contact between the ROBOT and the TRAILER (other than the Trailer Hitch) must be BUMPER-to-BUMPER. There are no exceptions to this.

To be honest I don't see here where it is abundantly clear that both sides of the corner must have their own BUMPER segment. It is clear that "all exterior corners of the BUMPER PERIMETER must be protected by BUMPERS." and that "Both sides of the corner must be protected." It is easy to create a ROBOT BUMPER PERIMETER which meets the the two statements in 2. above which has a side that does not have bumpers on it, yet the side would be protected. I believe the ROBOT in question at the beginning of this thread could be such a case. All it takes is two sets of oblique angles as part of the BUMPER PERIMETER.

Paul,

You quote ..."all sides must have a bumper"... GDC clarifications. I would like to know where you found that quote. In the Manual, in the team updates, and in the Q&A in it's many replies to questions on this topic I can't find where the GDC has stated "all sides must have a bumper". If any one has knowledge of where, in the above venues they have, please show me.

If you think about this.... if they really wanted each side of the robot to have BUMPER(S) they just have to include in the Competition Manual or the Team Updates the simple statement "all sides must have BUMPERS". When it would be so easy to state "all sides must have BUMPERS", they don't; not in the Competition Manual, not in the Team Updates, and not even in the many replies to questions in the Q&A. In my mind it is doubtful that in all of this communication, all of these communicators have randomly avoided using this simple statement if it clearly expresses their intent. Therefore I don't think it is the GDC's intent to require all sides of a ROBOT to have BUMPERS.

Paul, I look forward to seeing you, and your team and ROBOT at Midwest, and Cory, if things work out you and your folks as well at Nationals, the best of luck to us all,

Scott